The elevation of cyclic AMP during the first 24-hours of an in vitro anamnestic antibody response to KLH markedly (2-3X) enhances this response. KLH also markedly increases the active transport of cyclic AMP into these lymph node cells (LNC). This active transport is T dependent, but is not required for augmentation of antibody synthesis by cAMP. A mixture of LNC treated with cholera toxin (CT) and LNC (KLH-primed) treated with KLH results in greater (2-3X) antibody production than LNC plus KLH alone. This enhancement was also observed when LNC plus CT were placed in one chamber and LNC plus KLH in another; the chambers were separated by Nucleopore membranes (0.4 microns). Efforts are being made to isolate putative soluble factor(s) responsible for this non-specific enhancement. Highly purified rabbit T and B LNC were prepared by affinity chromatography with Sepharose 6MB-anti-Fab columns. These purified LNC populations will be employed to investigate some of the mechanisms of KLH-induced active transport and cAMP regulation of the antibody response.